LONDON (Reuters) -- Britain's foreign secretary defended the capability of British troops in Afghanistan on June 25, saying the fact they are being reinforced by 10,000 U.S. Marines did not mean they had failed.

"I think it's quite the opposite," David Miliband told BBC radio before flying to a G8 foreign ministers' meeting in Italy for talks on Afghanistan, Iran, and the Middle East.

"It's a recognition of the changing nature of the insurgency and the focus the insurgency is bringing to attacks on Afghans and Britons in Helmand," he said, referring to the province in southern Afghanistan where 8,000 British troops are deployed.

"There are 40 nations contributing militarily in Afghanistan and it's the focus that the insurgency has brought to Helmand that is bringing extra Afghan and extra American troops there.

"That's not something that is a rebuke to anyone. It's what coalition means."

Britain took over responsibility for Helmand in mid-2006 and started a slow build-up of troops.

But in the past three years, the security situation in the vast desert-and-mountain province has changed little, with the Taliban remaining strong and foreign troops unable to hold on to large patches of territory for very long. U.S. and British commanders have acknowledged an effective stalemate.

Air Strikes

Partly as a result, the U.S. military, following President Barack Obama's plan to beef up forces in Afghanistan, is now deploying 10,000 Marines to the province. The goal is to reinforce British units and try to tip the balance back in NATO's favour ahead of Afghan presidential elections in August.

While defending Britain's role, admitted air strikes in which many Afghan civilians have been killed were damaging the ability to win over a frustrated local population.

"It is a large problem," he said. "There's no denying not just the human cost but also the reputational cost.

"We're there to protect Afghans, not to see them die in civilian incidents."

He said he welcomed new guidelines for troops laid out by the new U.S. commander in Afghanistan, General Stanley McChrystal, which are designed to reduce civilian casualties.

Addressing the situation in the border regions of Pakistan, Miliband said the U.S. policy of using Predator drones to target leaders of al Qaeda and the Taliban hiding out in the tribal areas was something the U.S. and Pakistan needed to discuss.

Britain quietly opposes the policy, believing that it does not give sufficient recognition to Pakistan's sovereignty.

"The relationship between the Pakistani military and the American military is a different set of issues," he said.

"There is an issue for the Americans to sort out with the Pakistanis about drone attacks on al Qaeda high-level targets on the Pakistan side of the border."